surroundings in their movement toward, and placement in, positions within the economic system on criteria that put a premium on maximization of specific capacities that are closely related to measurable economic efficiency." Of course, some sociologists would view detachment quite differently. They believe separation "from family origin and surroundings" results in social deprivation leading to social and personal disorganization. But this is a problem to be addressed later.
Educational A ttainment
Migrants to large cities have higher educational attainment than the populations from which they originate. Aside from age, the selective factor of education probably has more generality than any other to be advanced. It is not that migrants have high educational attainment; most from rural areas have 6 years of education or less. It means only that they have more than the average of their origin population. For Calcutta (34) and for Bombay (35) it was found that in-migrants had "considerably higher" average educational attainment than the populations of origin, but lower average attainment than the populations in the two communities of destination. Much the same conclusion was reached for Lagos by Ejiogu (37). The Monterrey findings indicate a high degree of educational selectivity. For Cedral, 22 percent of those who had ever migrated had completed 6 years or more of schooling, whereas only 13 percent of the nonmigrants had attained this level.
In the Ghana study the relationship to education is very clear, as indicated by Table 4. The Caldwell study also is of interest in showing the way language competence is related to propensity to migrate. For male rural respondents over 20 years old, the percent who had never migrated by "literacy category" is as follows:
African only 67
English and African 50
English only 38
The educational system stimulates out-migration because it forces young people to leave the community if they are to complete their education. Only rarely do rural communities have facilities going beyond primary school. Since higher educational facilities most often are found in cities, the student has little recourse but to go there. Excepting the few specializations in agriculture, his training is such as to prepare him for urban jobs. In short, everything is stacked against the probability that those who attain an education much beyond the average for the population in their communities of origin will remain there.rant selectivity can be seen by reference to Kuznets' concept of "detachment" (36, xxxiii). He believes that detachment facilitates economic progress. "Indeed, we cannot exaggerate the importance of this detachment of wide groups of the population, particularly among the young generation, from family origin andbelief to this effect. Ravenstein (21, p. 199) stated as one of his laws, "Females are more migratory than males," butThe conclusion to be drawn from this is that if economic opportunity and living conditions in the cities were to be improved, return migration rates would he lower.an, et al. (1 3, Ch. 1). Substantively, Ghana differs from Mexico in the predominantly male rural-urban migration, in the multilingual character of the society, in the existence of polygamy, and